2019-01-17T07:16:05ZPreparation, characterization and application of keratin based green biofilms from waste chicken feathershttp://hdl.handle.net/10204/10599
Preparation, characterization and application of keratin based green biofilms from waste chicken feathers
Tesfaye, T; Sithole, Bishop B; Ramjugernath, D
Landfill disposal of synthetic plastics poses one of the biggest threats to the environment due to their non-biodegradability. This problem can be solved by production and use of biodegradable polymers instead. Feathers are a renewable, inexpensive, biodegradable, and easily available by-product of the poultry industry. They have long been considered as a solid waste that poses a serious environmental and economic problems. Avocado seeds are an organic waste that is also disposed of by landfilling. The aim of this study was to beneficiate these two organic wastes via development of green biofilms prepared from starch and keratin extracted from waste avocado seeds and waste chicken feathers, respectively. The films were then studied for their morphological structure, fine detail structure, crystallization behavior, functional group content, moisture content, solubility, tensile properties, moisture regain, and dissolution characteristics. Data on dissolution, water absorption, solubility, moisture content, mechanical properties and morphological structures of the keratin/starch blended films imply that the films could be used in the food packaging industry (as a cost-effective and environmental alternative source of raw material to the commonly used petroleum based materials used in packaging materials; as a raw material in the manufacture of hygiene products, e.g., superabsorbent materials for diaper products; and as a source of raw material for manufacture of biomedical products such as artificial skin products; and in the pharmaceutical industry (e.g., in drug delivery systems).
Open access article published in International Journal of Chemical Sciences, vol. 16(3): DOI: 10.21767/0972-768X.1000281
2018-08-01T00:00:00ZUCT943, a next-generation plasmodium falciparum PI4K inhibitor preclinical candidate for the treatment of Malariahttp://hdl.handle.net/10204/10585
UCT943, a next-generation plasmodium falciparum PI4K inhibitor preclinical candidate for the treatment of Malaria
Brunschwig, C; Lawrence, N; Taylor, D; Abay, E; Njoroge, M; Basarab, GS; Le Manach, C; Paquet, T; Cabrera, DG; Mancama, Dalubuhle T
The 2-aminopyridine MMV048 was the first drug candidate inhibiting Plasmodium phosphatidylinositol 4-kinase (PI4K), a novel drug target for malaria, to enter clinical development. In an effort to identify the next generation of PI4K inhibitors, the series was optimized to improve properties such as solubility and antiplasmodial potency across the parasite life cycle, leading to the 2-aminopyrazine UCT943. The compound displayed higher asexual blood stage, transmission-blocking, and liver stage activities than MMV048 and was more potent against resistant Plasmodium falciparum and Plasmodium vivax clinical isolates. Excellent in vitro antiplasmodial activity translated into high efficacy in Plasmodium berghei and humanized P. falciparum NOD-scid IL-2R null mouse models. The high passive permeability and high aqueous solubility of UCT943, combined with low to moderate in vivo intrinsic clearance, resulted in sustained exposure and high bioavailability in preclinical species. In addition, the predicted human dose for a curative single administration using monkey and dog pharmacokinetics was low, ranging from 50 to 80 mg. As a next-generation Plasmodium PI4K inhibitor, UCT943, based on the combined preclinical data, has the potential to form part of a single-exposure radical cure and prophylaxis (SERCaP) to treat, prevent, and block the transmission of malaria.
2018-09-01T00:00:00ZScreening of potential bioremediation enzymes from hot spring bacteria using conventional plate assays and liquid chromatography - Tandem mass spectrometry (Lc-Ms/Ms)http://hdl.handle.net/10204/10558
Screening of potential bioremediation enzymes from hot spring bacteria using conventional plate assays and liquid chromatography - Tandem mass spectrometry (Lc-Ms/Ms)
Jardine, JL; Stoychev, Stoyan H; Mavumengwana, V; Ubomba-Jaswa, E
The search for an eco-friendly, non-toxic, economical and efficient means of cleaning water through bioremediation is not only more favourable but critical to maintaining water quality globally especially in water-scarce countries. Thermophilic bacteria including Bacillus species are an important source of novel enzymes for biotechnology applications. In this study, 56 bacterial isolates which were cultured from five hot springs in South Africa were identified predominantly as Bacillus sp. or Bacillus-related spp by 16S rDNA gene sequencing. These isolates were screened for potentially useful enzymes for water bioremediation. Using conventional agar plate assays, 56% (n = 43), 68% (n = 38) and 16% (n = 31) were positive for amylase, protease and bromothymol blue decolorisation respectively. In liquid starch culture, three amylase-positive isolates differentially degraded starch by 34% (isolate 20S) to 98% (isolate 9T). Phenol degradation revealed that five out of thirty reduced phenol up to 42% by colorimetric assay. A thermophilic strain of Anoxybacillus rupiensis 19S (optimal growth temperature of 50 °C), which degraded starch, protein and phenol, was selected for further analysis by tandem LC-MS/MS. This newer technique identified potential enzymes for water bioremediation relating to pollutants from the food industry (amylase, proteases), polyaromatic hydrocarbons and dye pollutants (catalase peroxidase, superoxide dismutase, azoreductase, quinone oxidoreductase), antibiotic residues (ribonucleases), solubilisation of phosphates (inorganic pyrophosphatase) and reduction of chromate and lead. In addition, potential enzymes for biomonitoring of environmental pollutants were also identified. Specifically, dehydrogenases were found to decrease as the level of inorganic heavy metals and petroleum increased in soil samples. This study concludes that bacteria found in South African hot springs are a potential source of novel enzymes with tandem LC-MS/MS revealing substantially more information compared with conventional assays, which can be used for various applications of water bioremediation.
Copyright: 2018 Academic Press - Elsevier. Due to copyright restrictions, the attached PDF file only contains the abstract of the full text item. For access to the full text item, please consult the publisher's website. The definitive version of the work is published in Journal of Environmental Management, vol 223(1), pp 787-796
2018-07-01T00:00:00ZA geospatial modelling approach to simulating the impact of future planning policies on the City of Tshwanehttp://hdl.handle.net/10204/10539
A geospatial modelling approach to simulating the impact of future planning policies on the City of Tshwane
Ludick, C; Le Roux, Alize
Many researchers believe that no matter what path a country takes towards economic development the end result will lead to urbanisation. Rapid urban growth will have a major influence on the social, economic and political dialogue over the next few decades. The planning policies that are implemented in cities influence where urban growth will take place. In order for a government to implement effective policies they first need to establish what the possible effects of these policies could be. Land use change models have proven to be effective decision support tools when it comes to determining the effects of planning policies. The aim of this paper is to simulate urban growth for the City of Tshwane over the next 30 years under the Compaction and Densification Strategy policy currently in the process of implementation. This policy aims to reduce the effect of urban sprawl by promoting urban densification. It became clear from the results that the implementation of the Compaction and Densification Strategy could lead to the development of a more compact City of Tshwane. Under the Compaction and Densification Strategy, most of the development will take place within a 25km radius of the Central Business District and around major routes, metropolitan- and urban cores. This leads to most of the development taking place around the existing infrastructure instead of taking place where there is no established infrastructure.
Paper presented at the AfricaGEO 2018 Conference, 17-19 September 2018, Emperors' Palace, Johannesburg, South Africa
2018-09-01T00:00:00Z